The goals of the Phase l research period are to construct and test new amperometric biosensors for the determination of several serum enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT), which are frequently associated with alcohol-related organ damage and alcoholism. The sensors are based on the selective detection of products formed by reactions which are catalyzed by these serum enzymes. A novel sensor design permits efficient operation where interference due to dissolved oxygen and spurious current measurements due to common interferents (e.g., ascorbate, urate) are minimized. During Phase II, this technology will be extended to the selective detection of other laboratory markers of alcoholism, such as creatinine, urea, and glutamate dehydrogenase. The optimized sensors could serve an important role in the daily clinical practice of differential diagnostics of alcohol-related organ damage and in follow-up studies of alcoholism treatment programs.